Field Of The Invention
The present invention relates to improvements in the field of papermaking machines and, more particularly, to an improved controlled deflection roll and an improved structural relationship between the roll shell and the support shaft.
In press rolls in papermaking machines, a rotatable roll shell is mounted and supported on a fixed axis or beam extending through the roll shell. Hydrostatic supporting elements carried on the shaft support the shell and apply a supporting force on the shell, urging it toward a nip formed with a co-acting roll. Many varied forms of hydrostatic and hydrodynamic supports have been provided for supporting the roll shell on the shaft and applying a nip-loading force to the roll shell in the support plane. In this structure, means are provided for positioning the ends of the roll shell relative to the shaft in a lateral direction at right angles to the support plane. In a preferred arrangement, the guide arrangement for the ends of the roll shell holds the roll shell in position laterally but permits movement of the roll shell in the direction of the support plane. Various devices have been employed for this, and one arrangement is to utilize a flat-sliding surface parallel to the roll axis. This structure, which is shown and described in U.S. Pat. No. 3,885,283, makes it difficult to provide adjustable mating surfaces. It is also difficult and costly to provide optimum sliding clearance by holding close machining tolerances. If operating clearance is too tight, there can be increased friction and possible binding. If the clearance is too loose, vibration can result with inaccurate guiding. In addition, separate surfaces must be employed to carry axial thrust loads in that the roll shell must be held in a constant axial location on the shaft, and axial forces and thermal expansion create problems to maintain this alignment axially between the roll shell and supporting shaft.
It is accordingly an object of the present invention to provide end guide means between the roll shell and supporting shaft in a controlled deflection roll which avoids disadvantages heretofore present with available structures.
A further object of the invention is to provide an improved end guide means between the ends of a roll shell and a supporting shaft in a controlled deflection roll wherein the end guide means support axial thrust loads and permit free movement of the ends of the shell in a radial direction for opening and closing the nip with an opposing roll.
A still further object of the invention is to provide improved end guide means for the ends of a roll shell in a controlled deflection roll which are simplified in construction and provide a simplified way of adjustment which prevents binding and keeps friction to a minimum.